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fiction; the earliest use of the term has

been traced to a series of short stories itten in the 1970s by David Gerrold.

In 1972 Gerrold employed virus theme for a sci-fi potboiler called When HARLIE

Was. HARLIE was an acronym for Human Analogue Robot Life Input Equivalents

computer, which meant simply that the ficional creation could duplicate every

function of the human brain—a sort of mechanical equivalent of Dr.

Frankenstein’s monster. This robot could also dial up other computers by telefone

and reprogram them or modify data. In so doing, HARLIE was emulating a computer

program called simply virus, which dialed up telephone numbers at random. When

it found another computer at the end of the line, it loaded a copy of itself onto

the new machine, which started dialing other comlters to transfer copies of the

program, and so on. Soon hundreds of computers were tied up randomly calling

numbers.

 

The Virus program was fictional, of course, and simply part of Gerrold’s

convoluted plot, but the concept of a computer program reproducing itself had

been foreseen as early as 1948. In that

John van Neumann, a Hungarian-born mathematician and computer pioneer who had

designed one of the world’s first comruters, quaintly called Maniac, began

theoretical work on what was then thought of as electronically created

artificial life, which he termed automata. He predicted that the reproduction

process for such automata would be fairly simple.

 

Later, in the 1960s, before the advent of computer games, university

engineering students sometimes amused themselves by seeing who could write the

shortest program that could reproduce an exact copy of itself. These were

called selfreplicating programs, but van Neumann would have recognized them as

versions of his concept of electronic automata.

 

The first attempts to use selfreplicating programs for something useful were

made at Xerox’s Palo Alto Research Center in the late seventies. Two

researchers, John Shoch and Jon Hupp, devised what they called a worm program

to help with the management of the center’s computer network, which linked over

one hundred medium-sized machines. They envisaged the program working

automatically, archiving old files, making backup copies of current files, and

running routine diagnostic checks; they hoped that it would be able to perform

the endless housekeeping tasks that the researchers at Palo Alto were too busy

to keep up with. They named the new program a worm, the two later said, in

honor of their inspiration—another work of science fiction by the English

writer John Brunner called The Shockwave Rider, published in 1975. Brunner’s

book heralded the existence of a computer program, which he called a

“tapeworm,” that reproduced itself endlessly and couldn’t be killed.

 

Something very similar happened to Shoch and Hupp. Their worm program was

expected to sit quietly on one computer during the day, then emerge at night to

roam the computers in the research center, carrying out housekeeping chores.

 

Because it worked only at night, skeptical colleagues nicknamed it the vampire

program.

 

In their first test, Shoch and Hupp left the worm program “exercising” on half

a dozen designated machines in the lab. It wasn’t programmed to do anything; it

was just expected to travel to the designated machines and leave copies of

itself. The next morning, though, when the two arrived back at their office,

they found that the worm had escaped and had rampaged through all the

hundred-plus networked computers in the center. More disturbing it had

reproduced so quickly that it had brought every machine to a halt, seemingly

strangling them by taking up all available space in the computers’ memory.

 

Worse, when they attempted to restart one of the computers, the worm was

reactivated and proceeded to strangle the machine again. To destroy the worm,

they had to write another program—a killer program. Fortunately, unlike Brunner’s tapeworm, their

program was not indestructible, but Shoch and Hupp later called its behavior

“rather puzzling,” and simply abandoned the experiment, leaving unsolved the

problem of “controlling [its] growth while maintaining stable behavior.”

 

In the early 1980s a number of computer science students suc-

- ceeded in writing selfreplicating programs for the new Apple II computers.

Joe Dellinger, a student at Texas A&M University at the time, became intrigued

by the idea that computer programs could become modified when copied. He had no

trouble writing a selfreplicating program for the Apple II, even though he

didn’t consider himself a particularly clever programmer. His biggest problem

was in writing a program that wouldn’t cause damage; he was surprised at how

quickly the program could propagate, moving rapidly from computer to computer

by diskette, eventually traveling to machines outside the A&M campus.

 

Though Dellinger was intrigued by the notion that programs change as they

replicate and travel from computer to computer, there is nothing metaphysical

about it. It is simply a computer error. The longer and more complex a program

is, the more likely that a line of instruction, a command within the program,

will be skipped or altered in the copying process. These tiny modifications

rarely cause problems, but the potential for error is there.

 

What is more important is that Dellinger discovered that any selfreplicating

program, no matter how benign, carried with it the potential for damage, just

as a fly buzzing about a room carries the possibility of disease. Unlike the

software sold by commercial houses, selfreplicating programs are untested, untried and generally unstable. The changes created when these

programs transfer themselves from machine to machine can cause them to be

damaging, and their very presence on a computer is inherently risky.

 

Equally intriguing is the speed at which they propagate. In an environment like

a university campus, where anyone has access to any computer and programs are

routinely carried from machine to machine on diskette, they can multiply

exponentially. They are, after all, designed to replicate, so that one copy

quickly becomes two, two become four, four become eight, and so on. Dellinger

found that once let loose, the program’s spread was almost unstoppable.

 

It was another four years, however, before selfreplicating programs became

“viruses.” In 1983 and 1984 a graduate student at the University of Southern

Califomia named Fred Cohen was experimenting with these programs and, at the

suggestion of his adviser, decided to call them computer viruses. It was a

catchier name, and also became the title of his 1985 doctoral thesis, in which

he offered an explanation of viruses. A virus, he wrote, is “a program that can

infect other programs by modifying them to include a slightly altered copy of

itself.” Further, “every program that gets infected can also act as a virus and

thus the infection grows.” Cohen also indicated that viruses presented a threat

to computer security and could modify or damage data.

 

The thesis did not break any new ground in terms of computer science: in

essence, Cohen took the known characteristics of selfreplicating programs and

renamed them viruses. The term itself suggests that the programs are created in

some kind of wild electronic biosphere and are capable of spreading incurable

diseases from computer to computer—the high-tech equivalent of the biological

viruses to which they are often compared. The sensationalistic use of the word

would later prove to be fortuitous to computer security experts and have an

irresistible appeal to rogue computer programmers. Though the word was perhaps

chosen innocently, the metaphor was not entirely apt. Computer viruses, like

biological viruses, are spread unknowingly, and they can mutate while

spreading, but they are not created in the same way. Biological viruses are

carried by small, natural organisms, over which man has little control;

computer viruses, however, are simply programs—and computer programs are

written by people.

 

Cohen’s work quickly attracted attention, not least from a German computer

system engineer named Ralf Burger. At the time, Burger was twenty-six and

living in a small town near the Dutch-German border, not far from the city of

Bremen. Burger became fascinated by the concept of viruses, and in July 1986 he

had succeeded in creating his own, which he called Virdem. It was, to all

intents and purposes, a simple selfreplicating program, but with a small

twist. For Burger, the “primary function of the virus is to preserve its

ability to reproduce.” After being loaded onto a computer, Virdem was

programmed to hunt down and infect other files in the machine. When there were

no more files to infect, the virus would begin “a randomly-controlled gradual

destruction of all files.”

 

In December 1986 Burger decided to attend the annual convention of the Chaos

Computer Club in nearby Hamburg. The club had been founded in 1981 by Herwart

Holland-Moritz—who prefers to be known as Wau Holland—and is a registered

nonprofit organization. Holland, who was a thirty-two-yearold computer

programmer at the time, set up the club as a hobby; despite the sinister

implications of the name, it was chosen only because “there is a lot of chaos

in the application of computers.” According to the club’s constitution, it is

dedicated to freedom of information.

 

Since its foundation the club has proven itself adept at organizing media

events, and this ability together with the connotations of its name have given

the group a high profile. Like many clubs, Chaos unites people with a wide

range of interests: there are members who see computers as a weapon for

sociological change, others who simply want to play computer games, those who

want to know how computer systems work, and those concerned with making a fast

buck, legally or illegally. The Chaos members refer

to themselves as data travelers, rather than hackers, but they all share the

same obsession with computers and all vaguely subscribe to a vague notion of

“hacker ethics.” Their own unique understanding of that term is that they have

a mission to test, or penetrate, the security of computer systems. Early Chaos

Clubbers were allied with the VAXbusters, the group that sought to break

through the security of VAX computers around the world. The club’s first brush

with notoriety, though, occurred in 1984, when they broke into Btx, or

Bildschirmtext, an on-line text and information service patterned after

Britain’s Prestel. In 1986 they captured the media’s attention again when,

after the meltdown of the Soviet nuclear reactor in Chernobyl, they provided

alternative information on contamination levels by hacking into government

computers and releasing the data that they found. Their findings were

sufficiently at odds with official reassurances to make them the darlings of

Germany’s Green movement.

 

The annual conferences of the Chaos Club were held in Hamburg, always in

December. They attracted the cream of the German hacker community, as well as

observers from throughout Europe and elsewhere; were always well covered by the

media; and, without a doubt, were carefully watched by the local police. Each

conference was given a theme that was designed to excite media attention, and

in 1986 the theme was computer viruses.

 

Even though little was known about viruses at the time, the conference

organizers hoped piously that the publicity given to the subject would help

dispel myths. The organizers also declared: “The problem isn’t computer

viruses, but the dependence on technology,” and they blamed the writing of

viruses on “bad social condition(s) for programmers.”

 

The star performer at the conference was Ralf Burger, simply because he had

actually written a virus, which in those days was something of a feat. To prove

that his virus, Virdem, would work, Burger handed out copies to some two or

three hundred interested delegates. He said it would “give users a chance to

work with computer viruses.”

 

Technically, any virus is little more than a selfreplicating program with a

sting in its tail. This sting, usually known as the payload, is what the virus

actually does to the computer, which is often nothing at all—apart from

replicating, or performing a harmless joke, such as making a ball bounce around

the screen or instructing the

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